40 replies to this topic

[digger]

ok iv got my black powder to the fastest i can get with by ball mill and corning, so i would like to take the next step by using a hydraulic press.

could anyone tell me would a 6 tonne bottle jack be enough for pressing black powder.

also how important is a pressure gauge can one do without.

I am sure you will be able to use a 6 tonner, it will only ultimately affect the diameter of the puck you can process. I feel a pressure gauge is extremely useful as it allows you to press things to a repeatable pressure.

I personally have a 30 tonne press with pressure gauge (overclocked slightly as I can push it to 50 tonne) and I rarely have it above 6 tonne. I press a 1lb rocket to 5 ton.

[Bonny]

I am sure you will be able to use a 6 tonner, it will only ultimately affect the diameter of the puck you can process. I feel a pressure gauge is extremely useful as it allows you to press things to a repeatable pressure.

I used to use a 6 ton jack and it nicely pressed 2" diameter pucks. I now use a 12ton and press 3" diameter pucks. I have a guage and pump to about 8000psi (IIRC), then allow the powder to settle and repeat 2 more times over about 20 min.

POST # 500

Edited by Bonny, 26 May 2009 - 05:13 PM.

[Arthur Brown]

The force of the jack is applied to the area of the tool piston. SO a small jack will press small pucks and a big jack larger pucks.

A reference text will have data on the pressure applied to the puck to create a high density product. then you have to achieve that reliably by calculating the tool size and determining the applied force.

There is a Hydraulic dial pressure gauge available ( wolter I think) and there are electric strain gauge devices too, though I don't know the supplier.

Yes for good product pressure and time do matter.

[Gavin]

ok iv got my black powder to the fastest i can get with by ball mill and corning, so i would like to take the next step by using a hydraulic press.

could anyone tell me would a 6 tonne bottle jack be enough for pressing black powder.

also how important is a pressure gauge can one do without.

A 6 tonner will definately do pucks of around 7cm diameter weighing 50g. If you're only pressing BP you can do without the gauge. Press to the max using the lever supplied with the jack, let it dwell for 10 seconds or so and release the pressure gently. Chink, chink!

[Arthur Brown]

pucks compressed with 4% water/alcohol mix will press more easily than pucks pressed dry. Just you have to wait for them to dry slowly.

[Bonny]

I use 8% water (with about 10% alcohol added to reduce surface tension and speed drying). IMO the dwell time is very important, and I think you should allow to dwell WAY longer than 10 second, as the powder is still compressing.

[Arthur Brown]

Consider keeping the pressure on for some minutes if you want to get best use from the press and powder.

[Greenman]

could anyone tell me would a 6 tonne bottle jack be enough for pressing black powder.

To be honest, i have been using a 2 tonn for quite a while. The only reason i upgraded it recentely was for the need of pressing bigger rockets. I used my two tonns for pressing pucks, small rockets and fountians, and it worked wonders!

The choice is up to you, but if your thinking about pressing pucks only i suggest 2 tonn is good enough. Unless your going for real big scale. Keep in mind that the more tonns you go, for the harder it will be to conscruct a relaiable pressbody. My two tonn body was a very easy set up, just a few 2x4" wood pieces bolted together. However if you want your press to handle anything coming in, you might go for a 10tonn. More tonnes is futile.

[digger]

thank you all for your help on this subject. i decided though i may only use 2 ton to do my bp at the moment, I seem to outgrow everything i buy. so i decided to get a 10 ton press with a gauge

came today, though I have to fit a blast shield, I'm still nervous like hell with that amount of pressure on the bp. But ill get used to it.

I remember the 1st time I used my ball mill with bp just thinking of the chances of it self igniting. Now i don't even give it a second thought

Don't let familiarity make you become complacent.

1 tonne or 100 tonnes on your bp in a sealed tube will have pretty much the same results. My rams now have a designed in weakness so any blast is directed upwards (hopefully it will only burn without a blast, albeit quickly).

[BrightStar]

1 tonne or 100 tonnes on your bp in a sealed tube will have pretty much the same results.

I'm hoping myself that a well-consolidated BP grain in cardboard would just split the tube with a loud bang as it burns from the point of ignition.

The increasingly elaborate whistle / strobe rocket press setups we're seeing used 'over the pond' seem like a different matter. Steel hose clamp supports, machined aluminium 'clam shells' etc. just seem like shrapnel in waiting when pressing comps that can and do occassionally detonate...

Edited by BrightStar, 02 June 2009 - 07:31 PM.

[digger]

oh i total agree, it's like a false sense of safety since you cant see the danger, but i suppose this is one hobbies that you cant eliminate all dangers, all i can do is take as much safety measures as possible and hope if something does go wrong one of the safety measures will protect me.

one of the reasons i have decided to put a 1/2 inch think sheet metal as my blast shield and iv put a extension hose on so i can be 2 meters away.


how sensitive is bp under pressure ?? (has anyone on the forum had bp ignite while being pressed)

You can mitigate most risks with careful planning though. My mill is remotely operated in a bunker out on a field. If it did go bang then no-one would be hurt.

That would be a truly strong blast shield. Bloody heavy though 80cm by 100cm would weigh 80Kg I assume you have a floor standing press with it securely anchored so that it does not topple over with that mass attached to it.

[digger]

I'm hoping myself that a well-consolidated BP grain in cardboard would just split the tube with a loud bang as it burns from the point of ignition.

The increasingly elaborate whistle / strobe rocket press setups we're seeing used 'over the pond' seem like a different matter. Steel hose clamp supports, machined aluminium 'clam shells' etc. just seem like shrapnel in waiting when pressing comps that can and do ocassionally detonate...

I use clam shells as they are far quicker to use and you can get very good consolidation using them. Hence I use rammers designed to relieve so the clam shell will direct any force upwards.

P.S. without a tube support the card tube will split before any pressure ever registers on the gauge (well maybe the needle will just start to move).

Edited by digger, 02 June 2009 - 05:08 PM.